The influence of ALH 84001 on our understanding of the origin and evolution of Mars
Kevin Righter Abstract
ALH 84001 is an orthopyroxenite that is the oldest known Martian meteorite. Given this rock type and age, and the possible source locations, ALH 84001 represents an opportunity to learn more about basic geologic relations in the Martian highlands in the southern hemisphere. Its orthopyroxene‐rich mineralogy is unique and also includes C‐, S‐, P‐bearing minerals. ALH 84001 can provide constraints on chronology, geology and surface features, crust formation, paleomagnetism, weathering, climate, magmatism, and interior structure. When it was recognized to be of Martian origin (~1994), there were ~12 known Martian meteorite samples. That number is now >150, with only one other meteorite (NWA 7034) having clasts that are similar in age to ALH 84001. Thus, it remains a unique sample and continues to provide opportunities to understand this early period of Martian history.